A system of two or more pulleys (the tackles) each enclosed by a housing (the block) with a rope or cable threaded between them, usually used to lift or pull heavy loads
A lifting device consisting of one or more pulley blocks reeved with chains, wire ropes, or fibre ropes used solely for raising and lowering a load or moving a load horizontally
n. An apparatus of pulley blocks and ropes or cables used for hauling and hoisting heavy objects. a piece of equipment with wheels and ropes, used for lifting heavy things. Combination of pulleys with a rope or cable, commonly used to augment pulling force. Two or more of the pulleys are attached to a fixed block, and the remaining pulleys are free to move as well as rotate. A block and tackle can be used to lift heavy weights or to exert large forces in any direction. Higher force ratios may be obtained by the use of more pulleys, but this advantage may be offset by increased friction